cleanup the first non-dust htlc

lightning/src/ln/functional_tests.rs

@@ -10687,8 +10687,19 @@ fn do_test_nondust_htlc_fees_dust_exposure_delta(features: ChannelTypeFeatures)
 	nodes[1].logger.assert_log("lightning::ln::channel",
 		format!("Cannot accept value that would put our exposure to tx fee dust at {} over the limit {} on counterparty commitment tx",
 			expected_dust_exposure_msat, threshold_dust_exposure_msat), 1);
-	let _ = nodes[1].node.get_and_clear_pending_msg_events();
+	check_added_monitors!(nodes[1], 1);
+
+	let updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
+	assert!(updates.update_add_htlcs.is_empty());
+	assert!(updates.update_fulfill_htlcs.is_empty());
+	assert_eq!(updates.update_fail_htlcs.len(), 1);
+	assert!(updates.update_fail_malformed_htlcs.is_empty());
+	assert!(updates.update_fee.is_none());
+	nodes[0].node.handle_update_fail_htlc(nodes[1].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
+	commitment_signed_dance!(nodes[0], nodes[1], updates.commitment_signed, false);
+	expect_payment_failed!(nodes[0], payment_hash, false);
 
+	// Send an additional non-dust htlc the other way using the pre-calculated route above, and check for an immediate complaint from `FundedChannel`
 	unwrap_send_err!(nodes[1], nodes[1].node.send_payment_with_route(route_1_0, payment_hash_1_0,
 			RecipientOnionFields::secret_only(payment_secret_1_0), PaymentId(payment_hash_1_0.0)
 		), true, APIError::ChannelUnavailable { .. }, {});